Add MediaStream.active attribute

Source/modules/mediastream/MediaStream.cpp

Index: Source/modules/mediastream/MediaStream.cpp
diff --git a/Source/modules/mediastream/MediaStream.cpp b/Source/modules/mediastream/MediaStream.cpp
index 0d1316fce47446adaa440ece32304835305598e3..3ca7cb419c6a6a7068a5d81d084c85b3523ecf88 100644
--- a/Source/modules/mediastream/MediaStream.cpp
+++ b/Source/modules/mediastream/MediaStream.cpp
@@ -117,6 +117,10 @@ MediaStream::MediaStream(ExecutionContext* context, PassRefPtr<MediaStreamDescri
         newTrack->registerMediaStream(this);
         m_videoTracks.append(newTrack);
     }
+
+    if (emptyOrOnlyEndedTracks()) {
+        m_descriptor->setActive(false);
+    }
 }
 
 MediaStream::MediaStream(ExecutionContext* context, const MediaStreamTrackVector& audioTracks, const MediaStreamTrackVector& videoTracks)
@@ -143,6 +147,9 @@ MediaStream::MediaStream(ExecutionContext* context, const MediaStreamTrackVector
 
     m_audioTracks = audioTracks;
     m_videoTracks = videoTracks;
+    if (emptyOrOnlyEndedTracks()) {
+        m_descriptor->setActive(false);
+    }
 }
 
 MediaStream::~MediaStream()
@@ -150,6 +157,22 @@ MediaStream::~MediaStream()
     m_descriptor->setClient(0);
 }
 
+bool MediaStream::emptyOrOnlyEndedTracks()
+{
+    if (!m_audioTracks.size() && !m_videoTracks.size()) {
+        return true;
+    }
+    for (MediaStreamTrackVector::iterator iter = m_audioTracks.begin(); iter != m_audioTracks.end(); ++iter) {
+        if (!iter->get()->ended())
+            return false;
+    }
+    for (MediaStreamTrackVector::iterator iter = m_videoTracks.begin(); iter != m_videoTracks.end(); ++iter) {
+        if (!iter->get()->ended())
+            return false;
+    }
+    return true;
+}
+
 bool MediaStream::ended() const
 {
     return m_stopped || m_descriptor->ended();
@@ -167,11 +190,6 @@ MediaStreamTrackVector MediaStream::getTracks()
 
 void MediaStream::addTrack(MediaStreamTrack* track, ExceptionState& exceptionState)
 {
-    if (ended()) {
-        exceptionState.throwDOMException(InvalidStateError, "The MediaStream is finished.");
-        return;
-    }
-
     if (!track) {
         exceptionState.throwDOMException(TypeMismatchError, "The MediaStreamTrack provided is invalid.");
         return;
@@ -190,16 +208,17 @@ void MediaStream::addTrack(MediaStreamTrack* track, ExceptionState& exceptionSta
     }
     track->registerMediaStream(this);
     m_descriptor->addComponent(track->component());
+
+    if (!active() && !track->ended()) {
+        m_descriptor->setActive(true);
+        scheduleDispatchEvent(Event::create(EventTypeNames::active));
+    }
+
     MediaStreamCenter::instance().didAddMediaStreamTrack(m_descriptor.get(), track->component());
 }
 
 void MediaStream::removeTrack(MediaStreamTrack* track, ExceptionState& exceptionState)
 {
-    if (ended()) {
-        exceptionState.throwDOMException(InvalidStateError, "The MediaStream is finished.");
-        return;
-    }
-
     if (!track) {
         exceptionState.throwDOMException(TypeMismatchError, "The MediaStreamTrack provided is invalid.");
         return;
@@ -224,8 +243,10 @@ void MediaStream::removeTrack(MediaStreamTrack* track, ExceptionState& exception
     track->unregisterMediaStream(this);
     m_descriptor->removeComponent(track->component());
 
-    if (!m_audioTracks.size() && !m_videoTracks.size())
-        m_descriptor->setEnded();
+    if (active() && emptyOrOnlyEndedTracks()) {
+        m_descriptor->setActive(false);
+        scheduleDispatchEvent(Event::create(EventTypeNames::inactive));
+    }
 
     MediaStreamCenter::instance().didRemoveMediaStreamTrack(m_descriptor.get(), track->component());
 }
@@ -285,6 +306,10 @@ void MediaStream::streamEnded()
     if (ended())
         return;
 
+    if (active()) {
+        m_descriptor->setActive(false);
+        scheduleDispatchEvent(Event::create(EventTypeNames::inactive));
+    }
     m_descriptor->setEnded();
     scheduleDispatchEvent(Event::create(EventTypeNames::ended));
 }
@@ -324,10 +349,16 @@ void MediaStream::addRemoteTrack(MediaStreamComponent* component)
     m_descriptor->addComponent(component);
 
     scheduleDispatchEvent(MediaStreamTrackEvent::create(EventTypeNames::addtrack, false, false, track));
+
+    if (!active() && !track->ended()) {
+        m_descriptor->setActive(true);
+        scheduleDispatchEvent(Event::create(EventTypeNames::active));
+    }
 }
 
 void MediaStream::removeRemoteTrack(MediaStreamComponent* component)
 {
+    ASSERT(component);
     if (m_stopped)
         return;
 
@@ -357,6 +388,11 @@ void MediaStream::removeRemoteTrack(MediaStreamComponent* component)
     track->unregisterMediaStream(this);
     tracks->remove(index);
     scheduleDispatchEvent(MediaStreamTrackEvent::create(EventTypeNames::removetrack, false, false, track));
+
+    if (active() && emptyOrOnlyEndedTracks()) {
+        m_descriptor->setActive(false);
+        scheduleDispatchEvent(Event::create(EventTypeNames::inactive));
+    }
 }
 
 void MediaStream::scheduleDispatchEvent(PassRefPtrWillBeRawPtr<Event> event)